For example, if you are 28, it would look like this: 220 - 28 = 192 x 70% = 134 beats/minute.

To check your heart rate during exercise, count your pulse for 10 seconds, then multiply by 6. Compare this to your target rate.

A quick and easy way to assess your level of exertion is to do the "talk test" while exercising. Rate your ability to talk on a scale from 1-10, with 1 being no breathlessness and easy conversation and 10 being extreme breathlessness and inability to talk during exercise.

If you rate your level of breathlessness between a 1 and 4, you can have a somewhat regular conversation while working out and you are working below 50-60% of your maximum heart rate.

If you rate your level of breathlessness between 5-10, your sentences are broken, or you are only able to get in a few words and you are working at 70% or above your maximum heart rate.